Heating coil



Aug. 3, 1943.

H. A. STRICKLAND, JR

HEATING COIL Filed Sept. 19, 1941 INVEN TOR Harold f7 Sblb/Zhnd J11 BY%A P/fw ATTORNEY Patented Aug. 3, 194a 2,325,810 HEATING COIL Harold aStrickland, In, Detroit, Mich, assignor to Budd Wheel Company,Philadelphia, Pa., a.v corporation of Pennsylvania Application September19, 1941, Serial No. 411,579

6 Claims.

My invention relates to electric coils of the type most commonlyrequired for use in furnaces for the heating of metals byelectromagnetic induction.

It is required that these coils be provided with high capacity means forremoving heat from the coil itself and with convenient means for pairingthe number of turns Within the coil itself. The high capacity means forremoving heat from the coil consists in many cases in forming the coilof a tubular conductor and passing water through difierent portions ofthe coil in a number of parallel water cooling circuits. This requires anumber of difierent water taps to the tubular conductors. Changing thenumber of turns in the coil als requires a number of different taps.

The outstanding feature of my invention is the construction of thesewater taps in the electrical connections to render them more eificientand, at the same time, to render the construction of the coil itselfsimple, efficient and inexpensive,

This outstanding aim I have obtained by constructing the coil over allin a plurality of separate sections which, when placed end to end,constitute the coil as a whole, by diverting the ends of each sectionoutwardly from the contour of the adjacent end turns of the section, byarranging these diverted ends to overlap each other in planes whichsubstantially comprehend the portions of the turn from which theyemanate, by matching the adjoining 180 or the endmost turns of adjoiningor contiguous section ends in such manner that the two 180 turnstogether constitute a single turn of the same contour as complete turnsof the respective sections, the taps so formed being thus at themidpoint of such turn, whereby the coil as a whole may be comprised ofsingle turns throughout about a common axis, and by affording commonwater and electrical connections between and to the taps so formed;Other objects of my invention are the provision'in connection with thetaps themselves for cle'ansingthe cooling water or other cooling mediumcirculated through the tubular conductors of the coil, the arrangementfor convenient and quick cleansing of the taps and the coils, strong andquick electrical connections to the taps in orderly and simple fashionand staunch yet simple mounting for the water and electrical connectionsthemselves. 'Ihersame mounting may be used for the mounting of the coilbut I-prefer to'use a supplemental mounting for the coil. 1

In the accrimpanying drawing is shown the embodiment of my inventionbest known to me but, of course, there are others which are possible andwhich should be comprehended in the claims which are annexed to thisspeciflcation.

Of the drawing,

Figure l is a side elevation showing the right hand end of the structurebroken away to reveal the insulating and coil structure more fully;

Figure 2 is. a plan view with the portions of the heating unit embodyingthe coil broken awaynumeral H applied to brackets in Figures 1 and 2 andto coil ends in Figures 3 and 4. These sections ii are constructed ofseparate sections of tubular conductor, each of appropriate length toform its own portion of the coil l0 as a whole. The coil and sectionsare indicated as comprised of circular turns although they may be of anyshape and together form a continuous helix about a common axis it. ofuniform diameter throughout, each turn being like each other turn of thehelix.

The ends l3 of the endmost turns I4 of each section H are diverted fromthe main body of the turns M, as clearly appears in each of Figures 1 to4, and particularly in Figures 3 and 4, to form the taps 15. These endsl3 and the taps l5 which they together form immediately adjoin thecontour of the endmost turns 14. The ends 7 I3 are overlapped on eachother in the plane of the endmost turns 14 from which they emanate, orsubstantially a plane since the plane is helical and is not a trueplane. The arrangement is such that the adjoining of the conductorsection II immediately adjoining or contiguous to it forms a completeturn joined in its mid-section by the ends l3 constituting the taps i5,and

having the same contour for the turn as all other turns of the sectionsand of the coil in as a whole,

whereby there is uniformity of turns throughout the coil lll'as a whole.

The ends I3 which overlap substantially in the 2 plane of the turnareelectrically connected together byj solderingor otherwise in theoverlapped portions, and are hydraulically connected together for theintroduction and discha go of cooling fiuid by pipe coupling members itas shown inthe general form of pipe reducers hav-- ing alarge end Hsurrounding the overlapped ends l3 and soldered or otherwiseconnectedthereto. The coupling members havetheir reduced ends l8 ofgreater or less length connected with the fittings through which thewater or other cooling fluid is to be supplied. The re-- duced ends 118are circular and serve as 'convenient, simple and sturdy terminals forthe'electrical connections 59 which are made thereto from the bus bars26. located below them and parallel to the common plane in whichthecoupling members i5 lie. Members l9 are in the formof clamping lugs,their upper ends provided with circular portions clamped-around thereduced ends l8-by horizontally split clamping sections 2| and theirlower ends clamped to the bus barsZfl (separated by insulationZZ) bybolts 23.

Thelonger of the reduced ends 18 are provided at their outer ends withhousings having main bodies 25 in line with said reduced ends. I8 andwater-tube'connecting nipples 25 at right angles to the main body 25.Removable plugs 26' confine removable strainers (not shown) in place inthe strainer housings 24, whereby any strainer may be convenientlyremoved for cleansing merely by removing plug 26. The shorter reducedends cooling entrance and discharge manifolds the bars-3D engaging aboutthe round outer'ends of the T 21 and the rounded bodies of the longerreduced ends IS, the spacing laterally of the bars 38 of the fittings 21on the one side andthe fittings 2t on the other being such as to permitthis engagement.

The bus bars 20 together with the clamping members 35! afford astructural unit of support for the electrical and cooling medium tapsystem described. These members 28 and 30 may also serve-to assist inthe mounting of the coil thereupon but, as aforesaid, I prefer to mountthe coil otherwise (by means not shown since not a part of the instantinvention). V

The arrows applied to Figure .2 .of the drawing show the direction ofintroduction and discharge, respectively, of the cooling medium throughthe reduced ends l8. 'It will, be apparent, by noting these arrows, thatevery other tap I5 constitutes a means of introduction of cooling mediumand the alternate taps constitute means of discharge. They arenot-necessarily across coil sections of an equal number of turns, thepresent illustrationshowing sections H of but three turns each on theleft and sections ll of five turns each on the right. Thu there areprovided by the tap system multiple parallel paths for circulation ofcooling medium through the tubular conductors of the coil as a whole.The electrical connections K9 are shown in this construction as but two,the

;;2',s 5,8 1 o I v i one at the extreme'left and other at the extremevright, the entire number of turns of the coil bein connected across thebus bars 20.} Obviously, however, these connectors may be shifted fromone tap it toanother all the way along the coil. r I

The coil turn is shown as provided with various insulations inside andout, but, inasmuchas these insulations do not'constitute a part of thein stant invention,'they have not been described herein. The waterpassage above the nipples and 28 is shown-as being of insulatingmaterial whereby the convolutions are substantiallyin serieselectrically.

What is claimed is:

,1. In an electric furnace an electrical conductive tubular coil havingmulitple coil sections and formed of hollow conductors, the conductorends of adjacent sections being diverted radially outward from the coil,the diverted ends lying in' a common transaxial plane and the associatedendmost turns of the coil sections forming together a turn ofsubstantially the same pitch as the turns of the coil sections, wherebythesections together comprise a helicalcoil of uniform pitch.

2. In an electric furnace an electrical.con.- I

'ductive tubular coil having multiple coil sections and formed of hollowconductors, the conductor ends of adjacent sections being divertedoutwardly from thecoil, the diverted ends being parallel to each otherand contiguous, lying in. a

common plane'and immediately adjoining the portions of helical turns ofthe same curvature as the remaining turns of each of the sections,

whereby the taps do not distort the end turns of the sections fromwhichthey emanate and the 180 sections of the endmost turns which adjointhe taps form for each pair of taps a complete turn. of the same form asthe remaining turns of the sections. V

3. In an electric furnace, an electrical conductive tubular coil formedof hollow tubing and having multiple sections, the adjacent endsof thehollow tubing of the respective sections being turned outwardly-withreference to the coil axis and secured together to form taps for bothelectric and fluid transmission.

4. In a cooling coil system, a tubular coil formed of hollow conductorsand having multiple coil sections with conductor ends of contiguoussections outwardly turned and interconnected for common transmission ofa cooling medium, the adjacent half-end turns of adjacent coil sectionsforming a full turn of pitch uniform with-the coil section turns.

5.111 a cooling coil system, a tubular coil formed of hollow conductorsand having mul- I tiple coil sections, the conductor ends of adjacentcoil sections being outwardly turned and superimposed in a planetransverse to the coilaxis whereby the contiguous section coil turnsconform substantially in pitch to that of the other. 7

coil turns.

' 6. In an electric furnace, an electrically conductive tubular coilformed of hollow conductors and having plural coil sections, theconductor ends ofadjacent sections being out-turned and superimposed ina common plane whereby the coil is formed of turns of substantiallyuniform pitch i and continuity, means for uniting electrically andmechanically adjacent section ends and electrical circuit connectionssecured to at least one of said end uniting means.

HAROLD A..STRICKLAND, J a.

